Pass --no-defaults to embedded server to avoid that it reads any defaults file

mysql-test/mysql-test-run.pl:
  Pass "--no-defaults" to embedded server as "--server-arg=--no-defaults"

mysql-test/mysql-test-run.pl

@@ -3432,11 +3432,10 @@ sub mysqld_arguments ($$$$$) {
   if ( $glob_use_embedded_server )
   {
     $prefix= "--server-arg=";
-  } else {
-    # We can't pass embedded server --no-defaults
-    mtr_add_arg($args, "--no-defaults");
   }
 
+  mtr_add_arg($args, "%s--no-defaults", $prefix);
+
   mtr_add_arg($args, "%s--console", $prefix);
   mtr_add_arg($args, "%s--basedir=%s", $prefix, $path_my_basedir);
   mtr_add_arg($args, "%s--character-sets-dir=%s", $prefix, $path_charsetsdir);